Ask Singapore Homework?
Upload a photo of a Singapore homework and someone will email you the solution for free.
Question
secondary 3 | A Maths
2 Answers Below
Anyone can contribute an answer, even non-tutors.
need help with this qn, pls explain too
If you use the idea of similar triangles, x will be 78 deg since the corresponding length ratios are all 1 : 4.
If you use cosine rule (have you learnt it?), you get 82.8 deg.
I am thinking they want the 78 deg answer, but then again...
See 2 Answers
Having said that, I believe that the question wants you to put x = 78, since you have not learnt cosine rule but you have learnt similar triangles.
(Adjacent means “to the side”)
One of the adjacents will be the longest length of the triangle and it’s called the hypotenuse. The other is just an ordinary adjacent. Correct?
With a non-right angled triangle, the two adjacents are just ordinary adjacents.
c2 = a2 + b2 - 2ab cos C
But if your school teaches you
a2 = b2 + c2 - 2bc cos A
instead, then the “a” is the one in the opposite